The present disclosure relates to a surface planarization method of thin film and a preparing method of array substrate.
Dry etching, a processing technology commonly used in semiconductor manufacture field, usually utilizes a RF source to trigger plasma discharging in working gas, thereby generating ions and radicals which, under the effect of electrical filed, cause ion bombardment on substances on a substrate and exposed by a patterned layer of photoresist, so as to transfer patterns defined by a mask to the substrate.
The dry etching is typically configured for patterning a non-metallic layer such as a semiconductor layer during the preparation of an array substrate of a LCD (Liquid Crystal Display). Since it is usually performed in a form of ion bombardment, the dry etching severely damages the surface flatness of other film layers (e.g. a gate insulating layer in a TFT with a bottom-gate structure) below the etched layer, thus the film surface becomes rough. This on one hand adversely affects the growth of the metallic grains and the deposition of source/metallic layer, and on the other hand also adversely affects the transmittance and contrast ratio of the LCD.